Apple Mail Search is slow in IpadOS and iOS

Searching both a Gmail account and iCloud mail in Apple Mail on both iOS and iPadOS 18.1 is slow and incomplete. This is not new to iOS18. iPad Pro and iPhone15Pro both with adequate available space and both run fast in all other ways. Bandwidth is not an issue either. This IS a mail issue. I can usually complete a successful search on my Mac. On the iPad I get an incomplete search and a message about mail downloading, etc when the iPad is charging and locked, but I see no difference after an overnight charge and period of non use. I do have a lot of messages in Gmail and can be patient, but this goes beyond patience. Perhaps a way to reminder or similar?